diff --git a/utils/regr/corr.cpp b/utils/regr/corr.cpp
index 3c819b86d..9d12680ea 100644
--- a/utils/regr/corr.cpp
+++ b/utils/regr/corr.cpp
@@ -144,7 +144,7 @@ mcsv1_UDAF::ReturnCode corr::evaluate(mcsv1Context* context, static_any::any& va
 {
     struct corr_data* data = (struct corr_data*)context->getUserData()->data;
     double N = data->cnt;
-    if (N > 0)
+    if (N > 1)
     {
         double sumx = data->sumx;
         double sumy = data->sumy;
@@ -161,8 +161,7 @@ mcsv1_UDAF::ReturnCode corr::evaluate(mcsv1Context* context, static_any::any& va
         double var_popy = (sumy2 - (sumy * sumy / N)) / N;
         if (var_popy == 0)
         {
-            // When var_popy is 0, 1 is the result
-            valOut = 1.0;
+            // When var_popy is 0, NULL is the result
             return mcsv1_UDAF::SUCCESS;
         }
         double std_popx = sqrt(var_popx);
diff --git a/utils/windowfunction/wf_udaf.cpp b/utils/windowfunction/wf_udaf.cpp
index 5986c2872..2b7e28abc 100644
--- a/utils/windowfunction/wf_udaf.cpp
+++ b/utils/windowfunction/wf_udaf.cpp
@@ -84,6 +84,7 @@ void WF_udaf::resetData()
     getContext().getFunction()->reset(&getContext());
     fDistinctMap.clear();
     WindowFunctionType::resetData();
+    fValOut.reset();
 }
 
 void WF_udaf::parseParms(const std::vector<execplan::SRCP>& parms)
@@ -708,7 +709,6 @@ void WF_udaf::operator()(int64_t b, int64_t e, int64_t c)
     mcsv1sdk::mcsv1_UDAF::ReturnCode rc;
     uint64_t colOut = fFieldIndex[0];
     bool isNull = false;
-    fValOut.reset();
 
     if ((fFrameUnit == WF__FRAME_ROWS) ||
             (fPrev == -1) ||
diff --git a/utils/windowfunction/windowfunction.cpp b/utils/windowfunction/windowfunction.cpp
index c46259e4a..31ef6ed07 100644
--- a/utils/windowfunction/windowfunction.cpp
+++ b/utils/windowfunction/windowfunction.cpp
@@ -194,31 +194,21 @@ void WindowFunction::operator()()
                     // Built-in functions may have this functionality added in the future.
                     // If b > e then the frame is entirely outside of the partition
                     // and there's no values to drop
-                    if (b <= e)
+                    if (!firstTime && (b <= e) && fFunctionType->dropValues(prevFrame.first, w.first))
                     {
-                        if (!firstTime)
-                        {
-                            if (fFunctionType->dropValues(prevFrame.first, w.first))
-                            {
-                                // Adjust the beginning of the frame for nextValue
-                                // to start where the previous frame left off.
-                                b = prevFrame.second + 1;
-                            }
-                            else
-                            {
-                                // dropValues failed or doesn't exist
-                                // so calculate the entire frame.
-                                fFunctionType->resetData();
-                            }
-                        }
-                        else
-                        {
-                            fFunctionType->resetData();
-                            firstTime = false;
-                        }
+                        // Adjust the beginning of the frame for nextValue
+                        // to start where the previous frame left off.
+                        b = prevFrame.second + 1;
+                    }
+                    else
+                    {
+                        // If dropValues failed or doesn't exist,
+                        // calculate the entire frame.
+                        fFunctionType->resetData();
                     }
                     fFunctionType->operator()(b, e, i); // UDAnF: Calls nextValue and evaluate
                     prevFrame = w;
+                    firstTime = false;
                 }
             }
         }